US President Donald Trump today called British Prime Minister Theresa May after the London terror attack and pledged to continue "close collaboration" with the UK to stop attacks worldwide. <br/>' <br/>The White House said in a statement in Washington today that during the telephone call, Trump conveyed his sympathies and prayers for those injured in the attack.<br/>' <br/>An improvised explosive device (IED) exploded on a packed underground train at a London station today, injuring at least 22 people in the fifth terrorist attack this year. Prime Minister, Theresa May has said was the attack "clearly intended to cause significant harm".<br/>'<br/>